Assessment of Adequacy of Oxytocin Use in Pregnant Women Undergoing Induction of Labor [OP03-4C

Abstract

INTRODUCTION: Evaluation of adequacy of intrapartum management often includes quantification of oxytocin use, such as maximum rate of oxytocin used or length of time on oxytocin. Our objective was to evaluate a calculated measure that combines rate and time of oxytocin and its relationship with mode of delivery. METHODS: This is a secondary analysis of a randomized trial comparing speculum vs digital placement of Foley balloon for cervical ripening. Trial participants who did not receive oxytocin were excluded. Total dose of oxytocin received (OXYTOT) was calculated as the sum of the product of oxytocin rate and time on that rate for each concentration used. Area under the curve (AUC) was determined. Receiver operator characteristic (ROC) curves, and Wilcoxon rank sum test were used for analysis. OXYTOT was also categorized into deciles and its relationship to rate of cesarean section (CS) was studied. RESULTS: This analysis included 368 patients. Patients’ characteristics were similar in both CS and vaginal delivery (VD) groups. OXYTOT was predictive of mode of delivery (AUC of 0.62 95% CI 0.55-0.69). Women who underwent CS had a significant higher OXYTOT compared to women who had VD (9,308 vs 6,307 mIU, P<.0001). Rate of CS started significantly increasing at the 7th decile of OXYTOT (8,120 mIU). CONCLUSION: OXYTOT is a useful measure to assess adequacy of oxytocin use in induction of labor. CS rate remains low until high levels of this measure are reached. This measure may be a useful adjunct in assessing the quality of induction of labor and monitoring CS rates.